ONITSHA, Nigeria, May 16 (Reuters) - Nigerian workers from an oil labour union have extended a strike to oil majors Chevron, Shell and Eni subsidiary Agip in protest over the sacking of members from Exxon Mobil Corp, the union's general secretary said on Tuesday.

Lumumba Okugbara, of the Petroleum and Natural Gas Senior Staff Association of Nigeria (PENGASSAN), said union representatives would meet Exxon Mobil management on Tuesday for talks. Members of the union began a strike at Exxon Mobil last week. (Reporting by Anamesere Igboeroteonwu; Writing by Alexis Akwagyiram; Editing by Mark Potter)